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 Deep Learning


Generalization Bounds For Unsupervised and Semi-Supervised Learning With Autoencoders

arXiv.org Machine Learning

Autoencoders are widely used for unsupervised learning and as a regularization scheme in semi-supervised learning. However, theoretical understanding of their generalization properties and of the manner in which they can assist supervised learning has been lacking. We utilize recent advances in the theory of deep learning generalization, together with a novel reconstruction loss, to provide generalization bounds for autoencoders. To the best of our knowledge, this is the first such bound. We further show that, under appropriate assumptions, an autoencoder with good generalization properties can improve any semi-supervised learning scheme. We support our theoretical results with empirical demonstrations.


PVNet: A LRCN Architecture for Spatio-Temporal Photovoltaic PowerForecasting from Numerical Weather Prediction

arXiv.org Artificial Intelligence

Photovoltaic (PV) power generation has emerged as one of the lead renewable energy sources. Yet, its production is characterized by high uncertainty, being dependent on weather conditions like solar irradiance and temperature. Predicting PV production, even in the 24 hour forecast, remains a challenge and leads energy providers to keep idle - often carbon emitting - plants. In this paper we introduce a Long-Term Recurrent Convolutional Network using Numerical Weather Predictions (NWP) to predict, in turn, PV production in the 24 hour and 48 hour forecast horizons. This network architecture fully leverages both temporal and spatial weather data, sampled over the whole geographical area of interest. We train our model on a NWP dataset from the National Oceanic and Atmospheric Administration (NOAA) to predict spatially aggregated PV production in Germany. We compare its performance to the persistence model and to state-of-the-art methods.


Obstacle Tower: A Generalization Challenge in Vision, Control, and Planning

arXiv.org Artificial Intelligence

The rapid pace of research in Deep Reinforcement Learning has been driven by the presence of fast and challenging simulation environments. These environments often take the form of games; with tasks ranging from simple board games, to classic home console games, to modern strategy games. We propose a new benchmark called Obstacle Tower: a high visual fidelity, 3D, 3rd person, procedurally generated game environment. An agent in the Obstacle Tower must learn to solve both low-level control and high-level planning problems in tandem while learning from pixels and a sparse reward signal. Unlike other similar benchmarks such as the ALE, evaluation of agent performance in Obstacle Tower is based on an agent's ability to perform well on unseen instances of the environment. In this paper we outline the environment and provide a set of initial baseline results produced by current state-of-the-art Deep RL methods as well as human players. In all cases these algorithms fail to produce agents capable of performing anywhere near human level on a set of evaluations designed to test both memorization and generalization ability. As such, we believe that the Obstacle Tower has the potential to serve as a helpful Deep RL benchmark now and into the future.


Smelling Source Code Using Deep Learning

#artificialintelligence

Poor quality code contributes to increasing technical debt and makes the software difficult to extend and maintain. Code smells capture such poor code quality practices. Traditionally, the software engineering community identifies code smells in deterministic ways by using metrics and pre-defined rules/heuristics. Creating a deterministic tool for a specific language is an expensive and arduous task since it requires source code analysis starting from parsing, symbol resolution, intermediate model preparation, and applying rules/heuristics/metrics on the model. It would be great if we can leverage the tools available for one programming language and cross-apply them on another language. In this presentation, I would like to present our work on detecting smells using deep learning models.



DeepMind's superhuman AI is rewriting how we play chess

#artificialintelligence

Since 1997, when IBM's Deep Blue beat world champion and chess legend Garry Kasparov in a six-game match, chess players have accepted that machines are stronger at chess. We have taken some comfort from the fact that we taught these machines how to play. But strangely enough, despite being programmed by humans, traditional chess engines don't play quite like humans. Despite the hand-crafted heuristics, the fundament of an engine's superiority lies in calculation: sifting through vast numbers of moves to find concrete ways to solve a position. Back then, chess grandmasters were hired in to evaluate a series of typical positions and describe the considerations that led to the assessment, and then programmers turned these considerations into ever more sophisticated heuristics.


How TensorFlow makes Candy Crush virtual players

#artificialintelligence

Simulating a human gamer has enabled Candy Crush developer King to speed up its release cycles. The evolution of DeepMind's AlphaGo deep learning algorithm was the inspiration behind mobile games developer King's work to build a simulation of a games player using Google's TensorFlow. AlphaGo beat Go world champion Lee Sedol in 2016. To simulate the ancient game of Go, AlphaGo needed to play the game over and over again, applying a technique called a Monte Carlo search, which uses a deep neural network to "learn" what is the best play move to make. At the time, artificial intelligence (AI) researcher Demis Hassabis, co-founder of DeepMinds, which Google acquired in 2014, described how open source libraries for numerical computation using data flow graphs, such as TensorFlow, allow researchers to efficiently deploy the computation needed for deep learning algorithms across multiple CPUs or GPUs. According to GitHub's Octoverse 2018 report, TensorFlow was by far the most popular open source project in 2018.


Can SGD Learn Recurrent Neural Networks with Provable Generalization?

arXiv.org Machine Learning

However, due to the complexity raised by recurrent structure, they remain one of the least theoretically understood neural-network models. In this paper, we show that if the input labels are (approximately) realizable by certain classes of (nonlinear) functions of the input sequences, then using the vanilla stochastic gradient descent (SGD), RNNs can actually learn them efficiently, meaning that both the training time and sample complexity only scale polynomially with the input length (or almost polynomially, depending on the classes of non-linearity). We would like to thank Yingyu Liang and Zhao Song for very helpful conversations. Part of the work was done when Yuanzhi Li was visiting Microsoft Research Redmond. 1 Introduction Recurrent neural networks (RNNs) is one of the most popular models in sequential data analysis [25].When processing an input sequence, a recurrent neural network repeatedly and sequentially applies the same operation to each position of the input. The special structure of RNNs allows it to capture the dependencies among different points inside each sequence, which is empirically shown to be effective in many applications such as natural language processing[28], speech recognition [12] and so on. The recurrent structure in RNNs shows great power in practice, however, it also imposes great challenge in theory.


Deep Autotuner: A Data-Driven Approach to Natural-Sounding Pitch Correction for Singing Voice in Karaoke Performances

arXiv.org Machine Learning

We describe a machine-learning approach to pitch correcting a solo singing performance in a karaoke setting, where the solo voice and accompaniment are on separate tracks. The proposed approach addresses the situation where no musical score of the vocals nor the accompaniment exists: It predicts the amount of correction from the relationship between the spectral contents of the vocal and accompaniment tracks. Hence, the pitch shift in cents suggested by the model can be used to make the voice sound in tune with the accompaniment. This approach differs from commercially used automatic pitch correction systems, where notes in the vocal tracks are shifted to be centered around notes in a user-defined score or mapped to the closest pitch among the twelve equal-tempered scale degrees. We train the model using a dataset of 4,702 amateur karaoke performances selected for good intonation. We present a Convolutional Gated Recurrent Unit (CGRU) model to accomplish this task. This method can be extended into unsupervised pitch correction of a vocal performance, popularly referred to as autotuning.


Bayesian semi-supervised learning for uncertainty-calibrated prediction of molecular properties and active learning

arXiv.org Machine Learning

Predicting bioactivity and physical properties of small molecules is a central challenge in drug discovery. Deep learning is becoming the method of choice but studies to date focus on mean accuracy as the main metric. However, to replace costly and mission-critical experiments by models, a high mean accuracy is not enough: Outliers can derail a discovery campaign, thus models need reliably predict when it will fail, even when the training data is biased; experiments are expensive, thus models need to be data-efficient and suggest informative training sets using active learning. We show that uncertainty quantification and active learning can be achieved by Bayesian semi-supervised graph convolutional neural networks. The Bayesian approach estimates uncertainty in a statistically principled way through sampling from the posterior distribution. Semi-supervised learning disentangles representation learning and regression, keeping uncertainty estimates accurate in the low data limit and allowing the model to start active learning from a small initial pool of training data. Our study highlights the promise of Bayesian deep learning for chemistry.